(a) Field of the Invention:
The present invention relates to a chuck structure adapted for use with an electric drill, more particularly to a chuck structure that permits multiple operating modes of automatic percussion locking, manual locking and locking positioning of the drill bit by means of adjusting proper position of a movable shell.
(b) Description of the Prior Art:
A conventional chuck structure mainly includes a rotary shaft connected to a chuck. The chuck is externally provided with a rotatable outer shell and a fixed outer shell. The chuck is internally and annularly provided with inclined clamp pawls. The user can turn the rotatable outer shell to match rotation of threads to drive the clamp pawls to advance or withdraw obliquely so as to achieve clamping or releasing of the drill bit.
However, after locking, the rotatable outer shell is in a non-positioned state so that it may turn due to vibration or excessive torque so that the clamp pawls become loosened, which may result in dropping of the drill bit and may bring inconvenience and danger to the user.
The primary object of the present invention is to provide a combination type electric drill chuck structure in which a movable shell and a sleeve threaded seat are separated, and a force is applied to stop rotation of the movable shell during operation so that a percussion ring that originally rotates synchronously with the movable shell does not rotate, and rotational direction of the percussion ring is restricted. By matching action of a spring, the percussion ring can axially reciprocate to generate percussion with the sleeve threaded seat to thereby maintain tightness of threads and achieve an automatic locking mode.
Another object of the present invention is to provide a combination type electric drill chuck structure, in which the movable shell and the sleeve threaded seat are coupled so that by applying a force to rotate the movable shell, the clamp pawls can be brought to advance or withdraw obliquely to achieve drill clamping or releasing and a manual locking drill bit mode.
A further object of the present invention is to provide a combination type electric drill chuck structure, in which, by means of engagement of the movable shell and the fixed shell, the entire chuck assembly can be locked integrally so that the clamp pawls will not slip due to vibration or excessive torque to thereby maintain clamping force of the clamp pawls and achieve a drill bit locking positioning mode.
Still another object of the present invention is to provide a combination type electric drill chuck structure, in which after the drill bit locking positioning mode, a polygonal cavity of the sleeve threaded seat may be adapted for use in tightening or loosening of bolts in a sleeve use mode.